The Globe-Miami mining district in which the Van Dyke project occurs is known mainly for its large porphyry copper deposits, including the Miami-Inspiration, Miami East, Pinto Valley, Copper Cities and Castle Dome mines, and copper-bearing veins of the Old Dominion mine.

Porphyry copper deposits consist of disseminated copper minerals and copper minerals in veins, stockworks and breccias that are relatively evenly distributed throughout large volumes of rock. Porphyry copper deposits are typically high tonnage (greater than 100 million tons) and low to medium grade (0.3–2.0% Cu). They are the world’s most important source of copper, accounting for more than 60% of the annual world copper production and about 65% of known copper resources.

The geometry and dimensions of porphyry copper deposits are diverse, in part because of post-ore intrusions, varied types of host rocks that influence deposit morphology, relative amounts of hypogene and supergene ore each of which has different configurations, and erosion and post-ore deformation including faulting and tilting. Porphyry copper deposits commonly are centered on small cylindrical porphyry stocks or swarms of dikes.

The vertical extent of hypogene mineralization in porphyry copper deposits is generally less than or equal to 1 to 1.5km. The predominant hypogene copper sulphide minerals are chalcopyrite, which occurs in nearly all deposits, and bornite, which occurs in about 75% of deposits. Mol ........

The proposed mining method for copper recovery from the Van Dyke deposit is In-situ Copper Recovery methods (ISCR). ISCR has been selected because the Van Dyke deposit is near the town of Miami AZ. Further to this, the fractured nature of the host rock, the presence of saturated joints and fractures within the mineralized zone, and copper mineralization that preferentially occurs along fracture surfaces makes the project a good candidate for ISCR.

In-situ leaching of the oxide resource at Van Dyke is proposed to occur by an injection and recovery well system from underground galleries located just above the oxide deposit, within the Gila Conglomerate. Injection wells will deliver the leachate to the oxide zone, with recovery wells then transporting the dissolved copper in solution to the SX/EW plant at surface. The well holes will be drilled in angled fan patterns from underground galleries and follow an approximate 5-spot pattern with four recovery wells surrounding a single injection well in a repeating pattern, with the average distance between injection and recovery wells designed to be 21m. The final product on site is Grade A copper cathode (99.99% pure) for shipment to the market.

The mine development plan comprises an access ramp from surface for mobile equipment, two declines for access to the production galleries, gallery development within the targeted production zones, and service and ventilation facilities. All underground development is car ........

The processing plant will receive pregnant leach solution (PLS) from the In-situ Copper Recovery (ISCR) leaching operation. The plant will process between 580 to 3900 m3/hr, averaging 2,800 m3/h PLS and produce 38,555 t/year 85Mlb/year as LME grade copper cathode.

The main processing areas will include:
- Copper solvent extraction (SX)
- Copper electrowinning (EW)
- Bleed solution neutralisation
- Reagents and services

The SX circuit will consist of two extract stages and a single strip stage. Based on the expected iron and manganese concentrations in the PLS, a wash stage should not be required in this circuit.

Spent electrolyte from the copper electrowinning process will be used to strip the copper from the loaded organic back into the aqueous phase. The spent electrolyte will have a high sulphuric acid concentration (180 g/L) and this will reverse the extraction reaction, consuming sulphuric acid and producing copper sulphate.